| (19) |
 |
|
(11) |
EP 0 367 159 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
11.12.1991 Bulletin 1991/50 |
| (43) |
Date of publication A2: |
|
09.05.1990 Bulletin 1990/19 |
| (22) |
Date of filing: 28.10.1989 |
|
|
| (84) |
Designated Contracting States: |
|
DE GB |
| (30) |
Priority: |
31.10.1988 JP 275827/88
06.02.1989 JP 27263/89
20.03.1989 JP 68754/89
12.04.1989 JP 92437/89
17.04.1989 JP 96697/89
|
| (60) |
Divisional application: |
|
94117704.0 / 0640958 |
| (71) |
Applicant: Hitachi Maxell Ltd. |
|
Osaka-fu (JP) |
|
| (72) |
Inventors: |
|
- Nakazumi, Tetuya
Ikeda-shi
Osaka-fu (JP)
- Kishimoto, Mikio
Mishima-gun
Osaka-fu (JP)
- Sueyoshi, Toshinobu
Otokuni-gun
Kyoto-fu (JP)
- Kawarai, Seigi
Ashiya-shi
Hyogo-ken (JP)
|
| (74) |
Representative: von Kreisler, Alek, Dipl.-Chem. et al |
|
Patentanwälte
von Kreisler-Selting-Werner
Postfach 10 22 41
50462 Köln
50462 Köln (DE) |
|
| |
|
| (54) |
Magnetic recording medium comprising acicular alloy magnetic powder |
(57) An acicular alloy base magnetic powder comprising iron and cobalt, which has a major
particle size of not larger than 0.25 µm, an axial ratio of from 4 to 8, a cobalt
content of from 8 to 50 % by weight based on the weight of iron and saturation magnetization
of at least 120 emu/g after being kept standing at the temperature of 60°C and relative
humidity of 90 % for a week, which has improved corrosion resistance and can provide
a magnetic recording medium suitable for recording in the short wavelength range.